WASHINGTON (CNS)—The passage of state constitutional amendments that define marriage as the union of a man and a woman in California, Florida and Arizona might mark the end of a battle in those states, but it does not signal the end of the continuing fight over what marriage means.

And that's a fight in which the U.S. Catholic bishops plan to remain engaged for the long term.

"It's certainly encouraging that the citizens of Florida, Arizona and California chose to uphold the traditional definition of marriage," said Archbishop Joseph E. Kurtz of Louisville, Ky., chairman of the U.S. Conference of Catholic Bishops' recently created Ad Hoc Committee for the Defense of Marriage, in a Nov. 6 telephone interview.

The committee's work includes—but goes far beyond—public policy questions like the amendments approved Nov. 4. It is also charged with finding ways to promote healthy marriages and to answer "questions and misunderstandings" about the Catholic view on marriage, the archbishop said.

"There's lots of good news (about marriage), but there are also lots of challenges," he said.

In a postelection statement, Cardinal Roger M. Mahony of Los Angeles spoke about one of the biggest misunderstandings—that the Church's opposition to same-sex marriage indicates a rejection of homosexuals and lesbians as people.

"Proposition 8 is not against any group in our society," the cardinal said. "Its sole focus is on preserving God's plan for people living upon this earth throughout time.

"The Catholic Church understands that there are people who choose to live together in relationships other than traditional marriage," he added. "All of their spiritual, pastoral and civil rights should be respected, together with their membership in the church."

D. Michael McCarron, executive director of the Florida Catholic Conference, had a similar message after that state's voters approved the constitutional amendment.

"The bishops' support for Amendment 2 was not motivated by discrimination or animosity against gays and lesbians," he told the Florida Catholic newspaper. "The bishops see that both the common good and the future of our society are served through the traditional understanding of marriage, and they also understand that research and history support the traditional family as the best environment to nurture and raise healthy children."

With the addition of Florida, Arizona and California, 30 states now have constitutional amendments defining marriage as a union of one man and one woman. Same-sex marriages are permitted in Massachusetts and Connecticut, and some California officials have said they will continue to issue marriage licenses to same-sex couples until a judge orders them to stop.

An estimated 18,000 same-sex marriages have taken place in California since the state Supreme Court's ruling last May expanded the definition of marriage to include same-sex couples. The vote throws into confusion the legal status of those unions.

Opponents of Proposition 8 are challenging the amendment on several fronts.

A court filing Nov. 5 by the San Francisco and Los Angeles city attorneys and the Santa Clara County counsel argued that "such a sweeping redefinition of equal protection would require a constitutional revision rather than a mere amendment," according to a statement from San Francisco City Attorney Dennis Herrera's office. "Article XVIII of the California Constitution provides that a constitutional revision may only be accomplished by a constitutional convention and popular ratification, or by legislative submission to the electorate."

Proposition 8 "devastates the principle of equal protection" and threatens the rights of any potential electoral minority, Herrera said.

The American Civil Liberties Union and Lambda Legal also have challenged the election results, saying Proposition 8 is invalid because the initiative process "was improperly used in an attempt to undo the constitution's core commitment to equality for everyone by eliminating a fundamental right from just one group -- lesbian and gay Californians."

At least one pollster credits a late shift by Catholics with the win in California. Mark DiCamillo, director of the Field Poll, said polling by his San Francisco-based organization a week before the election found that 44 percent of Catholics favored Proposition 8 and 48 percent opposed it, roughly mirroring the survey results across all groups statewide. About a quarter of the state's voters are Catholic.

When the votes were counted, Proposition 8 won by a 52 percent to 48 percent margin.

Exit polls showed that Catholics made up 30 percent of the electorate in California, DiCamillo said, and 64 percent of them voted yes on Proposition 8—a 20 percent shift in one week. "Regular churchgoers showed a similar movement toward the yes side," he added. "Our final pre-election poll showed 72 percent of these voters voting yes, while the exit poll showed that 84 percent of them voted yes."

For DiCamillo, the most logical explanation is that Catholics and other churchgoers heard messages in church the weekend before Election Day that convinced them to vote for Proposition 8.

"My take is that polling on issues like same-sex marriage that have a direct bearing on religious doctrine can be affected in a big way in the final weekend by last-minute appeals by the clergy to their parishioners," he said.